Freight trains typically undergo a pre-departure terminal test in which the air brake equipment of each car is inspected prior to the train being cleared to proceed from the train make-up yard. This inspection requires a trainman to "walk the train" visually checking each car's brake equipment. Prior art type truck mounted brake assemblies include a piston travel indicator attached to the brake cylinder assembly for monitoring piston travel to determine whether or not the brake equipment is functioning properly.
The currently used piston travel indicator comprises an indicating means, such as a flag, which moves along a measuring means. This measuring means has an acceptable operating range or zone marked thereon. The inspector views the location of the flag with respect to the acceptable operating range to determine whether or not the braking equipment is functioning properly. For example, if the flag is below the range, then such would indicate that the slack adjuster trigger needs to be adjusted. If, on the other hand, the flag is above the range, such could indicate that either the slack adjuster is out of capacity and the brake shoes are too worn, or the slack adjuster is not functioning properly and requires maintenance.
Due to the location of this piston travel indicator within the truck mounted brake assembly underneath the car, it is often difficult for the trainman to readily view the indicator and to make a proper determination as to the functioning of the braking equipment. It thus becomes burdensome to inspect the braking equipment of the train and consequently more time consuming to complete the terminal test.